[Effect of intraventricular administration of naloxone on stress-induced hormonal reactions]

The purpose of the work is to bring to light the role of naloxone-blocked CNS opioid receptors in the implementation of hormonal reactions caused by stress agents in male Wistar rats. Naloxone was administered at a dose of 10 micrograms/100 g body mass into the lateral cerebral ventricles via preliminarily implanted polyethylene cannulas. Stress stimuli (cooling at -20 degrees C for 10 min. and administration of a foreign protein/sheep erythrocytes at a dose of 10(9) cells) followed 30 min. after naloxone administration. Stress-induced changes in the concentrations of aldosterone and testosterone were shown to be significantly disturbed in animals receiving naloxone whereas changes in the concentrations of corticosterone and ACTH remained the same as those in animals not receiving the agent. Changes in hormonal functions and a type of stress showed correlation. It has been assumed that naloxone-blocked CNS receptors are involved in the implementation of stress-induced reactions of mineralocorticoid function of the hypothalamo-hypophyseo-adrenal system and androgenic function of the hypothalamo-hypophyseo-gonadal system.